This invention relates to apparatus for compression crimping fibrous material such as yarn. More particularly, the compression crimping apparatus to which the present invention relates comprises at least one driven roller having a periphery adapted to engage the fibrous material for advancing the fibrous material and stationary walls defining a chamber for receiving the fibrous material from the roller and in which chamber the fibrous material is compressed, the chamber having a cross-section which has at least one corner and the periphery of the roller intercepting at least one corner of the cross-section of the chamber. In the present invention, means are provided for guiding the fibrous material which may ride along the roller periphery from one side of the roller to the other away from the corner as the fibrous material advances from the roller periphery into the chamber whereby the catching of fibers from the fibrous material at the corner is prevented. Generally, the periphery of the roller also intercepts another corner of the cross-section of the chamber. The apparatus of the invention also comprises means for guiding the fibrous material away from that other corner as the fibrous material advances from the roller periphery into the chamber whereby the catching of fibers from the fibrous material at the other corner is also prevented. Usually, there are two rollers, between which is defined a nip, the fibrous material being advanced by driven counter-rotation of the rollers while the fibrous material is received in the nip. The periphery of the second roller intercepts another two corners of the cross-section of the chamber and in the apparatus according to the invention, one of the means for guiding the fibrous material guides the fibrous material away from two of the corners and the other means for guiding the fibrous material guides the fibrous material away from the other two corners whereby the catching of fibers at all four corners is prevented.
Various apparatuses for compression crimping fibrous material are known which comprise at least one driven roller having a periphery adapted to engage the fibrous material for advancing the fibrous material and stationary walls defining a chamber for receiving the fibrous material from the roller and in which chamber the fibrous material is compressed, the chamber having a cross-section which has at least one corner and the periphery of the roller intercepting at least one corner of the cross-section of the chamber. Frequently, the aforementioned roller is paired with another driven roller so that a nip is defined therebetween, the rollers rotate in opposite directions and the fibrous material is received in the nip whereby it is advanced by the counter-rotation of the rollers. The periphery of each of the rollers intercepts two corners of the cross-section of the chamber. In the present invention, in apparatuses of the aforementioned type, it has been recognized that each of the corners of the cross-section of the chamber which is intercepted by a periphery of a roller is a problem in that fibers from the fibrous material tend to get caught at each such corner. The nature of the problem may be explained as follows. In the chamber into which the fibrous material is fed, the fibrous material is compressed. The compression of the fibrous material results in the fibrous material folding over onto itself and forming a plug. This imparts crimp to the fibrous material. Catching of fibers of the fibrous material at the aforementioned corners tensions the fibers and prevents them from being crimped to as great an extent as fibers which are formed into the plug without interference. The result of such catching is observed as a discontinuity in the integrity of the plug and what appears to be a void and is actually a zone of lower than average crimp in the crimped yarn. Uniformity of crimp is desired by users of the crimped yarn and, consequently, the aforementioned non-uniformity is undesirable.
It is, therefore, an object of the invention to improve crimping apparatus of the aforementiond type by providing means for preventing the catching of fibers of the fibrous material at each corner at which the periphery of one of the aforementioned rollers intercepts a corner of the cross-section of the chamber which receives the fibrous material from the roller and in which chamber the fibrous material is compressed, whereby a crimped yarn of improved uniformity is obtained.
Other objects and advantages of the present invention will be obvious to one skilled in the art from the following description of the invention.